The present invention relates to a wood screw.
A conventional wood screw has a head that is formed into a truncated conical shape. The wood screw is used by being attached to a retainer element, such as a wood material, a board, or a cloth-adhered board, that is to be attached to a wood material to be supported, such that the head of the wood screw is on the same plane as the surface of the retainer element.
However, when the wood screw is embedded into the retainer element, the head rotates while pressing against the retainer element by the rotation of the wood screw. Therefore, friction, expansion, and frictional heat occur. The head of the wood screw becomes embedded further into the retainer element than expected, causing a drawback in that the surface of the retainer element breaks.
Japanese Patent Laid-open Publication No. 2001-289223 is related prior art.